Re: [PATCH 1/6] xfs: don't try to mark uncached buffers stale on error.

From: Jeff Liu <jeff.liu@oracle.com>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 1/6] xfs: don't try to mark uncached buffers stale on error.
Date: Fri, 13 Dec 2013 12:47:16 +0800	[thread overview]
Message-ID: <52AA9154.9060308@oracle.com> (raw)
In-Reply-To: <20131212100947.GW10988@dastard>

On 12/12 2013 18:09 PM, Dave Chinner wrote:
> On Thu, Dec 12, 2013 at 05:30:14PM +0800, Jeff Liu wrote:
>> On 12/12 2013 13:34, Dave Chinner wrote:
>>> From: Dave Chinner <dchinner@redhat.com>
<snip>
>>
>> It seems there is no such kind of test cases in xfstestes for now, I'd
>> write one if required.
> 
> nothing quite that generic - xfs/087 does a loop like that over
> different log configurations, but that's testing log recovery more
> than shutdown sanity. Adding that test would be a good idea - it's a
> shame no other filesystem supports a shutdown like XFS does....
This is really an unique feature of us :), I'll write a case so.
>
>> The backtraces were shown as following:
>>
>> [  365.987493] INFO: task fsstress:3215 blocked for more than 120 seconds.
>> [  365.987499]       Tainted: PF          O 3.13.0-rc2+ #13
>> [  365.987500] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> [  365.987502] fsstress        D ffff88026f254440     0  3215   3142 0x00000000
>> [  365.987507]  ffff880253f19de0 0000000000000086 ffff880242071800 ffff880253f19fd8
>> [  365.987512]  0000000000014440 0000000000014440 ffff880242071800 ffff880073694c00
>> [  365.987515]  ffff880073694c80 ffff880073694c90 ffffffffffffffff 0000000000000292
>> [  365.987519] Call Trace:
>> [  365.987528]  [<ffffffff81718779>] schedule+0x29/0x70
>> [  365.987560]  [<ffffffffa0c2a49d>] xlog_cil_force_lsn+0x18d/0x1e0 [xfs]
>> [  365.987565]  [<ffffffff81097210>] ? wake_up_state+0x20/0x20
>> [  365.987570]  [<ffffffff811e8770>] ? do_fsync+0x80/0x80
>> [  365.987594]  [<ffffffffa0c28921>] _xfs_log_force+0x61/0x270 [xfs]
>> [  365.987599]  [<ffffffff812b0610>] ? jbd2_log_wait_commit+0x110/0x180
>> [  365.987603]  [<ffffffff810a83f0>] ? prepare_to_wait_event+0x100/0x100
>> [  365.987607]  [<ffffffff811e8770>] ? do_fsync+0x80/0x80
>> [  365.987629]  [<ffffffffa0c28b56>] xfs_log_force+0x26/0x80 [xfs]
>> [  365.987648]  [<ffffffffa0bcf35d>] xfs_fs_sync_fs+0x2d/0x50 [xfs]
>> [  365.987652]  [<ffffffff811e8790>] sync_fs_one_sb+0x20/0x30
>> [  365.987656]  [<ffffffff811bcc32>] iterate_supers+0xb2/0x110
>> [  365.987660]  [<ffffffff811e88c2>] sys_sync+0x62/0xa0
>> [  365.987665]  [<ffffffff81724ced>] system_call_fastpath+0x1a/0x1f
>> [  372.225302] XFS (sda7): xfs_log_force: error 5 returned.
>> [  402.275608] XFS (sda7): xfs_log_force: error 5 returned.
>> [  432.325929] XFS (sda7): xfs_log_force: error 5 returned.
>> [  462.376239] XFS (sda7): xfs_log_force: error 5 returned.
> 
> So what we see here is that there is a race condition somewhere in
> the shutdown code. The shutdown is supposed to wake everyone waiting
> of the ic_force_wait wait queue on each iclog, but for some reason
> that hasn't happened. The sleepers check for XLOG_STATE_IOERROR
> (which is set during the force shutdown before we wake ic_force_wait
> sleepers) before they go to sleep, so whatever the race is it isn't
> immediately obvious to me.
Now I basically can always reproducing this problem on SSD, so I'm
going to get involved in tracing down it.

Thanks,
-Jeff

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